The tale of the other dog

Website: https://sites.google.com/site/ismsip2013/

Preliminary experiment 1

Independent variable:  amount of vitamin mixture

Dependent: Size/growth of dog

Control: same amount of vitamin mixture

Aim: to see if the dog’s growth will be affected

Preliminary experiment 2

Independent: presence of vitamin mixture

Dependent: The difference in size of dog

Control: same amount of food

Preliminary experiment 3

Independent: Presence of vitamin mixture

Dependent: Difference in weight of dogs

Control: Same dogs, same water, same living conditions

	Experiment 1	Experiment 2	Experiment 2
Dependent variable	Size of dog	The difference in growth of dog	Difference in weight of dogs
Independent variable	Amount of vitamin mixture	Presence of vitamin mixture	Presence of vitamin mixture
Control Variable	Same amount of vitamin mixture	Same amount of food given	Twin dogs, same water given, same living conditions
Limitations

Questions for Discussion

1)    What traits characterise a good scientist? How does Tess Ting demonstrate these traits?

- Persistent. Tess Ting constantly tried to improve his experiment and countered the problems to achieve the result he wanted.

2) What was wrong with Tess Ting ’s first dog food experiment?

- He did not have a comparison (another dog) and cannot prove that the dog grows more.

3) What two mistakes did he make in his second experiment?

- 1. He did not get the same breed of dogs. 2. He did not feed the exact same food to both dogs.

4) What do you think was his hypothesis?

- The special vitamin mixtures allows the dog to grow more than that of another dog which only ate normal dog food.

5) What is his dependent and independent variable?

- The growth of the dog and the presence of vitamin mixture.

6) What is his controlled experiment and what did he control in it?

- The other dog, which was fed normal dog food and controlled both of their intake of food.

7) What is a control and why is it important in a scientific experiment?

- a control is to compare with the tested experiment and is important to prove the hypothesis of the experiment.

7b) What is a positive control? What is a negative control?

- Negative controls are groups where no phenomenon is expected. They ensure that there is no effect when there should be no effect.

- Positive controls are groups where a phenomenon is expected. That is, they ensure that there is an effect when there should be an effect, by using an experimental treatment that is already known to produce that effect (and then comparing this to the treatment that is being investigated in the experiment).

8)    What kind of record did Tess Ting keep? Do you think this is sufficient? Why?

-       identical collars hung brass letters of identical mass, saying "Dog A” and “Dog B.”

-       weight

-       Yes, because he took down all the information he needed

9)    Can you recreate Tess Ting’s experiment? Why is repeatability important in science?

- repeatability is important to ensure the reliability of the results.

      9b) is repeatability and reliability the same?

- No, repeatability is repeating the experiment multiple times but reliability is using the results of the repeated experiment to ensure a reliable and accurate result. Repeatability leads to reliability.

      10) What other kinds of experiments could you do to test Tess Ting’s conclusion about         the effect of his dog vitamins?

b) What is the difference between ‘affect’ and ‘effect’?

- Affect is a verb, meaning to cause something to happen. Effect is a noun, which is the result of having happened.

c) What is the difference between ‘correlation’ and a ‘causal’ claim?

- a relationship between two, or more, variables

- changes in one variable they measured directly caused changes in the other

VIDEO

1)   What do you think was the hypothesis?

- To see if cooking the food gave more nutrients to the body than raw food.

2)   What is the dependent and independent variable?

-       Dependent variable: The sugars produced after digestion

-       Independent: The cook or raw food

3)   What is the controlled experiment and what was controlled in it?

- The raw food. The amount

4)   What are the assumptions made in the experiment?

- The machine is able to digest food exactly the same as the human body

5)   Are there any areas for improvement or not reliable or valid?

-Repeatability