CHALLENGES THAT LEAVE THEIR MARK

Understand

Organise your ideas concept map

1 Summarise information in a drawing. Make a drawing to scale of an instrument used to measure length. Indicate its minimum height, maximum height, measurement interval and sensitivity. Give examples of measurements taken with it.

2 Conceptual map. Copy and complete the following concept map. Following the example, create one that summarizes the purpose of scientific knowledge and the types of language used to communicate the results of scientific inquiry.

Remember that you can find the answers to all calculation activities on anayaeducacion.es

Scientific knowledge

1 We all contribute. Explain in your own words what the scientific method is. Can you recall a situation in your everyday life in which you have used it, with or without knowing it?

2 What is your horoscope? Search on several horoscope websites for what they say will happen for someone with your horoscope tomorrow. Decide whether what you have read is scientific knowledge.

Physical and chemical changes

3 Physics and Chemistry are, among others, called experimental sciences. Why do you think that is? With what properties of scientific knowledge can you relate that fact?

4 Apart from the physical and chemical changes, there are other changes we can observe in nature: nuclear changes. Research them and write a definition. Then, create a table with the different types of nuclear changes and an example of each.

5 Classify the following changes as physical or chemical and explain your reasoning a) Vinegar reacting with marble. b) An egg frying. c) Formation of steam when water boils. d) Dilation of a metal beam. e) Iron heated until red hot. f) Digestion of an apple.

Physical quantities. Units and measurement

6 Give two examples of physical quantities and two other properties or traits that are not physical quantities and justify your answer. For each physical quantity, list at least two units other than SI units.

7 How wide is your desk? How tall are you? What is the distance between Madrid and Berlin? Why did you use the units you did for each case? Write the lengths in scientific notation and SI units.

8 In astronomy, distances are enormous and astronomers have defined appropriate units for them: a) 10 ms. b) 25 m. c) 42 mt.

– Astronomical unit (AU). This is defined as the mean Earth-Sun distance. It is 150 000 000 km.

– Light year. This is the distance light travels in a vacuum in a year at 300 000 km/s. It is 9.5 · 1012 km.

– Parsec (pc). This is 3.2616 light years. Write these units in SI, first without and then with scientific notation. Write parsecs and light years in AU.

9 What physical quantity could you measure with this instrument and what are the instrument’s properties?

11 Which lengths are written wrong? Why?

12 Thinking hats. Design a method for measuring the radius of the cylindrical base of a lamp post. Estimate the values and write the measurement.

Scientific language

13 From the following graph, which represents the distance travelled by a vehicle as a function of time: a) Make a table with at least five data pairs. b) Examine the relationship between the quantities and write in verbal and mathematical language. c) Find the mean velocity of the vehicle.

10 An airplane flies at 2 000 feet above sea level at 400 miles per hour (mph). Find the conversion factors you need to write this data in SI.

14 Shared interpretation. Write the relationship between the quantities plotted on the following graph in both verbal and mathematical language.

15 Newton’s second law, which you will study in future years, relates the force acting on an object with the acceleration it imparts. Its mathematical formula is:

F = m · a where m is the mass of the object. Write it in words, specifying the proportionality relationships you observe.