"An experiment should be conducted for a particular reason. A statement which explains what the experiment is attempting to achieve is known as an aim. The prediction that the scientist make who is undertaking the experiment is known as the hypothesis. In this section you will learn how to construct both an aim and a hypothesis for an experiment."
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1. Aim
What is an Aim?
An aim is a single statement that describe the purpose or reason for why we are conducting an experiment. An aim should be brief and concise. It should state the purpose of the experiment without providing a prediction. An aim usually starts with "To determine..."
An aim is a single statement that describe the purpose or reason for why we are conducting an experiment. An aim should be brief and concise. It should state the purpose of the experiment without providing a prediction. An aim usually starts with "To determine..."
Examples
Example 1
"Fred takes a basketball and drops it onto different surfaces. He uses a ruler to measure how high the basketball bounces on each surface. He drops the ball on cement, grass, water, gravel and sand. Each time he drops the ball from one meter then records the height of the first bounce. He repeats this three times for each surface. A possible aim for this experiment could be: "To determine if a basketball bounces higher on a harder surface." |
Example 2
"Mary took three items of food from her lunch box. She took a barbecue ring, a marshmallow and half a slice of bread. She then set up a Bunsen burner with a clamp. She clamped the barbecue ring and placed it over the Bunsen burner. She lit the Bunsen burner and left it for ten seconds then turned it off. She timed how long the burger ring burnt for using a timer. She repeated this for the other pieces of food. Mary found that the marshmallow burnt the longest, then the burger ring and then the bread." A possible aim for this experiment could be: "To determine if food with high amounts of energy (kilojoules) burn longer when lit." |
2. Aim - Practice Questions
Task: Write an appropriate aim for each of the following investigations on the answer sheet.
Investigation 1
"Georgia plants three seedlings in pots. She places each plant in a different spot in the classroom depending on sunlight. She place the first plant on the window sill where the sun shines all through the day; she places the second plant on the table at the front of the class where the sun only shines half the day; she places the last plant in the cupboard where it gets no light. She waters the plants equally and leaves them to grow for a week measuring how tall they get."
What is the aim of Georgia's experiment?
Investigation 2
"Cory makes a balloon rocket car. He builds the car out of a bottle, an axle and wheels. He tapes one balloon on the car, blows it up and then lets it run in a straight line. He measures the distance the car goes. Cory then adds another balloon and repeats the experiment with two balloons powering his car. He continues adding balloons and measuring the distance he gets."
What is the aim of Cory's experiment?
Investigation 1
"Georgia plants three seedlings in pots. She places each plant in a different spot in the classroom depending on sunlight. She place the first plant on the window sill where the sun shines all through the day; she places the second plant on the table at the front of the class where the sun only shines half the day; she places the last plant in the cupboard where it gets no light. She waters the plants equally and leaves them to grow for a week measuring how tall they get."
What is the aim of Georgia's experiment?
Investigation 2
"Cory makes a balloon rocket car. He builds the car out of a bottle, an axle and wheels. He tapes one balloon on the car, blows it up and then lets it run in a straight line. He measures the distance the car goes. Cory then adds another balloon and repeats the experiment with two balloons powering his car. He continues adding balloons and measuring the distance he gets."
What is the aim of Cory's experiment?
3. hypothesis
What is a Hypothesis?
A hypothesis is a statement that provides a possible answer to a scientific question. It is based on your prior knowledge, research and observations. Experiments are conducted to test hypotheses. A hypothesis must therefore be able to be tested through a scientific experiment. The results of the experiment will determine if the hypothesis is correct.
A hypothesis is a statement that provides a possible answer to a scientific question. It is based on your prior knowledge, research and observations. Experiments are conducted to test hypotheses. A hypothesis must therefore be able to be tested through a scientific experiment. The results of the experiment will determine if the hypothesis is correct.
Guidelines for Writing Hypotheses
- A hypothesis predicts what will happen.
- A hypothesis contains an "if... then..." statement.
- A hypothesis is not something already shown to be correct.
- A hypothesis is not a statement of personal opinion.
- A hypothesis is not a definition.
- The more specific and detailed a hypothesis is, the stronger it is.
- A hypothesis must be testable.
Examples
Example 1
"George conducted an experiment where he planted three seedlings. George watered the first seed with tap water, the second with salt water and the third with soapy water. He repeated this twice a day for two weeks." A possible hypothesis for this experiment could be: "If a plants are watered with tap water, then they will grow consistently." |
4. Hypothesis - Practice Questions
Task: Write a hypothesis for each of the following investigation on the answer sheet.
Investigation 1
"Sarah took ten identical iron nails and place them in a container. She painted half of the nails and left the rest unpainted. She then put the container of nails outside for a month. She recorded that the unpainted nails started to rust within 5 days. After 28 days the painted nails started to rust."
Write a possible hypothesis for Sarah's experiment?
Investigation 2
"Charlie took four identical cans. He painted two of the cans white and two black. He filled each can with one cup of water. He then placed all the cans in the sun. Charlie recorded the temperature of all the cans every 10 minutes. He found that the black cans were warmer than the white cans."
Write a possible hypothesis for Charlie's experiment?
Investigation 3
"Bianca took two balls with varying density. She recorded the density of each of the balls. She then went to her swimming pool and placed all the balls into the pool. The ball with the lowest density floated and the ball with the highest density sunk."
Write a possible hypothesis for Bianca's experiment?
Investigation 4
"Brady had three cups of water. The first cup had a temperature of 80°C, the second cup had a temperature of 40°C and the third cup had a temperature of 5°C. He put a tablespoon of sugar in each cup and stirred it in. As he stirred it he timed how long it took for the sugar to dissolve. The first cup dissolved the sugar the fastest, followed by the second and lastly the third cup."
Write a possible hypothesis for Brady's experiment?
Investigation 1
"Sarah took ten identical iron nails and place them in a container. She painted half of the nails and left the rest unpainted. She then put the container of nails outside for a month. She recorded that the unpainted nails started to rust within 5 days. After 28 days the painted nails started to rust."
Write a possible hypothesis for Sarah's experiment?
Investigation 2
"Charlie took four identical cans. He painted two of the cans white and two black. He filled each can with one cup of water. He then placed all the cans in the sun. Charlie recorded the temperature of all the cans every 10 minutes. He found that the black cans were warmer than the white cans."
Write a possible hypothesis for Charlie's experiment?
Investigation 3
"Bianca took two balls with varying density. She recorded the density of each of the balls. She then went to her swimming pool and placed all the balls into the pool. The ball with the lowest density floated and the ball with the highest density sunk."
Write a possible hypothesis for Bianca's experiment?
Investigation 4
"Brady had three cups of water. The first cup had a temperature of 80°C, the second cup had a temperature of 40°C and the third cup had a temperature of 5°C. He put a tablespoon of sugar in each cup and stirred it in. As he stirred it he timed how long it took for the sugar to dissolve. The first cup dissolved the sugar the fastest, followed by the second and lastly the third cup."
Write a possible hypothesis for Brady's experiment?